Update - Sorry I messed up. The Xoom actually has DDR2 but clocked at a slower speed.
Here's a comparison (and I've seen other similar ones) showing them both having DDR2 RAM and, interestingly, the TF with a 667MHz system bus compared to the Xoom with a 600MHz system bus. That could help explain why the TF shows faster benchmarks pretty much across the board.
I was on my phone when I posted my last comment so I couldn't copy the link easily.
Here it is http://www.nvidia.com/object/tegra-2.html
Frequency DDR2-667 (Tegra 250)
LPDDR2-600 (Tegra 230 and Tegra 250)
Memory Size Up to 1GB
Aha, so, that explains the discrepancy in performance between the Asus and the Xoom. It could also help explain why the Xoom seems to get better battery life than the Asus. Fascinating.
In this case, I'll take a faster system with somewhat less battery life, since the keyboard dock more than makes up for the difference.